Following up my previous post on how well-rounded I believe I am, I am realizing that being well-rounded is not good. At least, not in my position. Let's consider my position and see why being well-rounded but not deep in any particular skill is not good.
I work for a large company and it employs many people. MANY people. We have all kinds of engineers, technicians, secretaries, project managers, etc. If it can happen on a project chances are we've seen it and hired for it. Need someone to create a schedule and manage a budget? We've got project managers and they've got secretaries. Need someone to design an antenna feed? We have seasoned RF engineers. Need someone to program an 8-bit microcontroller, create interfacing electronics and build an enclosure for everything? Well, no. We don't need one person to do that when we could have three separate people do it. People who excel in their individual areas and can get the job done quicker and better than one person.
Let's be serious - you wouldn't combine all of those tasks into one person unless it was absolutely necessary or desirable. When might those confluence of events happen that make it necessary or desirable? Let's tackle necessary first. It might be necessary to do it with one person because that's all you have. You either can't find people who are skilled in those areas or you can't use them if you did find them. The skillset might not exist in your company if it's small and might not exist in your area if you're in a small town or other backwater type place (like most of where I grew up...). So you use what's available to you and hope that it can get you by. And it might be desirable. You could contract out the work but then you have communication issues and overhead costs and such. If the work isn't particularly difficult then it might not be worth it to bring new people on even if they could get it done in half the time. So a wide array of basic knowledge could be useful if you couldn't hire more people and didn't care too much about time lost and/or wasted.
But at a large company those don't generally hold true. You usually have a ready supply of many differently-skilled people. You probably have at least two people to choose from who have your skill, so you'll always choose the person who is better at what you want to do. Then this person gets more experience and hones his/her skill and eventually becomes an expert. Then, unless this person is unavailable, you will always go to this person if you need his/her skill. In the situation where two people know the skill but have unequal levels of experience, the more experienced person always wins.
And time is usually very important at a large company. There's never enough of it. Competition is fierce and to maintain market position you have to be timely. Contrast with a smaller business: there is little/no market position to maintain so releases of products can be more easily delayed without losing too much money over it. Not that deadlines aren't important to a smaller company, but if they let a deadline slip they are likely to lose less money than a large company, even as a percentage of income.
Both of these factors contribute to drive people to specialization in large companies. With so many people being available, you have to set yourself apart to make an impact. In some circumstances intimate knowledge of a project may make it more worthwhile that you perform multiple tasks with different skillsets yourself. Or they could just put the person with the right skillset underneath you and have you lead him/her.
That's the major difference: A large company is more able and more likely to trade labor for time, where a smaller company doesn't have this luxury. If you aim to be a jack of all trades, shoot for a small company that can't support many people.
Update: I've done a little thinking and I believe there are a couple more things to be said for this line of thinking. 1) The 'time first' mentality tends to push people towards specialization in skills and it also pushes entire organizations towards specialization in skills. If you know Labview and you can do the job in Labview, chances are you'll do it in Labview. So a C# programmer is going to have a hard time. Over time the company becomes a monoculture and tries to apply its one major skillset to all problems (for good or ill). 2) The 'time first' thinking need not be limited to skill sets. If you can buy an off-the-shelf product that does what you need then it makes no sense to build it in-house. You're essentially buying the skillset you need ready-made. This also can lead to a monoculture of suppliers - with certain businesses being preferred over others because of past experience. In and of itself, buying this experience rather than 'growing' it in-house is an acceptable tradeoff for certain decisions but definitely not all decisions. 3) The monoculture induced by either of the above methods can kill a business. If this trend moves forward to its logical conclusion (which is admittedly far-fetched) then you'll have a handful of experts skilled at using a small number of skills/products, or you'll just buy everything from someone else. You run into two problems with this: what happens when your extra-skilled engineers retire/get hit by a bus/find a better offer? Brain drain. What happens when all you do is buy other people's products and put them together? Brain drain again - you now have people whose sole skill is figuring out what other products to buy and re-sell. You're no longer an engineering firm - you're at best a project management firm and at worst a re-seller.
Neither of the above outcomes are guaranteed to happen. There are many other pressures that will come to bear on an organization before this brain drain becomes absolute. However, it may still become terminal before it is absolute and the organization may not survive. There are two ways to combat brain drain: First, never outsource (directly or by means of buying COTS products) your core competency. If you write e-commerce software then outsource your server management, not your programming. If you build Arduinos then outsource your board fabrication, not your board layout. If you do that then you are paying people to develop their skills at the expense of your own. Then, when they are the experts they have no reason to keep you around, or at least, no reason to let you have a big slice of the profit. Second, you must, MUST invest in pursuing different/new technologies and you MUST invest in training less-skilled people. If you have a choice between two people of different skill levels, consider choosing both. Split the work up along skill-level lines and let the less-skilled person cut his/her teeth on the easy stuff and let the more-skilled person handle the hard stuff. But keep them together - working together, seated together and give them the same access to resources/people. Chances are the less-experienced person is younger than the more experienced one and will be around longer than him/her. You'll need the same level of experience if not more in 20 years time, so plan for it!
It is less efficient to make these investments in lower-skill areas and people, but unless you plan for the future you could find your company on the chopping block.